How do u change gear box oil galant gsr 89

Hey i have a GALANT GSR 89 MANUAL i have a few problems with the gears that i want to get fixed. allot of the gears recently have been grinding:banghead: only when i slide it into gear and when its in it is fine:runaround:. i want to try and change the gearbox oil to see if that will fix it. i hope that the gearbox isn't dieing. if so how much does one cost?

My question> does anyone know where the gearbox drain plug and the plug where i fill it are? if anyone has a manual can u scan it and please upload it to me as i don't have one yet. < not the whole manual just the gearbox page.

thanks :)

Any one?